We propose a pilot study for a group that has been neglected in the Peruvian HIV epidemic, namely male sex workers (fletes). There is recent research in Peru on the prevalence and incidence of HIV and other sexually transmitted infections (STIs) among possible bridge populations such as heterosexually identified men (1-5), male sex partners of pregnant women (6), male clients of female sex workers (7), and men who have sex with men and women (8). However, there has been limited epidemiologic research and no prevention research focusing on fletes. Our research has demonstrated that fletes are an important component of the Peruvian HIV epidemic with specific social, cultural, and behavioral characteristics that place them at high risk for acquisition and transmission of HIV and STIs. Fletes engage in survival sex work for a very low wage and with significant pressure to accept all of the primarily male clients that solicit their services, limited ability t negotiate condom use, and low rates of condom use. Fletes also have numerous non-client female sex partners, with whom condom use rates are very low. We conducted a formative research study of the lives, sexual behaviors, and HIV/STI risks of two subpopulations in Lima, higher-income fletes based in more affluent neighborhoods and low-income fletes from the city's urban core. Results revealed high prevalences of HIV(23%) and syphilis (22%) infections among low-income fletes and an urgent need for HIV prevention interventions that specifically address the issues they face (Bayer et al, unpublished data). Our study findings and the dimensions of social action theory serve as the foundation for the proposed Skill-building Center for low-income fletes. The Center will provide a space for fletes to engage with each other and develop a sense of shared community while accessing: (1) fundamental life needs, (2) safe socialization opportunities, (3) basic healthcare, (4) HIV/STI risk reduction activities, (5) personal development activities, and (6) vocational training. We propose a pilot study that will assess potential effect size using a randomized design to compare intervention and comparison groups, in addition to evaluating feasibility, acceptability, retention, and contamination. We will evaluate three specific aims: Aim 1. To estimate the effectiveness of the intervention for reducing incidence of HIV and syphilis among fletes, the proportion of fletes' income derived from sex work, and the proportion of fletes reporting unprotected sex with clients. Aim 2. To assess the (a) feasibility and (b) acceptability of the intervention and identify factors that hindr or facilitate implementation. Aim 3. To test the effectiveness of strategies (a) to avoid contamination through participation of the comparison group in the intervention and (b) to retain all participants for follow-up in a longer-term study. Results of this study will be used to develo an R01 for the implementation and assessment of a longer-term intervention with fletes.